Well I got everything hooked up today on my 3400 swap fiero.

But i went to go take it for a small test drive and it is lacking in power big time. Im not even getting a signal to my tach either. Not sure what im missing here. It seems that the timing is way out or something. When you start it up and go to blip the throttle it will bog out if you give it to much gas to fast. It was very a discouraging day thats for sure. Just dont know what is wrong now. Any help would be nice.

Did you set the base timing? When you did, did you jumper the A & B pins on the ALDL terminal? Just off the bat it sounds like your timing is severly retarded.
Rich

can i set the base timing with out an external crank trigger though?

Sorry ... I misread your original post ... I read it as 3.4 not 3400


Rich

so anyone got some advice? I cant seem to get it running right.

If you are lacking power and not seeing tach signal, I know where I'd start looking.

As you may or may not know, the DIS will run the car (but only at fixed 10 deg) as long as it has 12V hooked up, even without the ECM being hooked to the ICM.

I'd be going through your wiring and making sure you have continuity from the relevant ECM pins (I assume you went with the 7730 ECM) to the relevant ICM pins.

Maybe i wired the DIS wrong. I have done a bit of reading and some people have said you need to ground the DIS to the block and not the ECM

Looking at ryans diagrams i noticed i may not have the tach signal tied into the c500 connector. My car is at the shop and i hevnt went out there today so im not 100% sure, but i dont remember tieing into the c500 with the DIS. The thing is though, My DIS only has a 4 wire system does not have the extra white wire to tie into the C500.

Wiring diagram here. http://www.gmtuners.com/fil...o_V6_to_7730_DIS.pdf

Would this even effect anything though? Is it not just a wire to run the tach and thats all?

EDIT: Pin C - Tach signal out is the wire I do not have on my DIS.

[This message has been edited by bandit307 (edited 06-07-2008).]

The Tach signal is not in the c500 connector. It's in the clear connector that sits just under the ECM in the vehicle. I don't remember the actual # of the connector right off the top of my head but the line is grouped with the harness that goes directly to the motor from inside the vehicle. You are using the 7730 ECM, right? did you remove the tach filter? I didn't use it on my engine swap and works just fine. If you still have it installed, try removing it. I've seen the terminals break off them after years of sitting in a hot engine bay. You just might have a loose connection.

Yes i am using the 7730 ECM. Does the wire for the Tach signal inside the cab not go to the C500 connector though? Im just going according to Ryan's diagrams.

Also, what am i looking for in terms of a tach filter? Never worked with one so no idea what it looks like or which wire it should be on.

The Tach filter from the original 2.5/2.8L motors is a white (if clean) capacitor about an inch long. It has a white connector on it and two lines, in & out from the capacitor. 2.5L motors had it beside the valve cover near the t-stat housing. 2.8L had it tucked behind the ignition coil.

Well I went and looked into my manual and I am wrong. Could have sworn it was in the clear/white connector but the book says otherwise. It is in the c500, it's white and in pin location C3
Sorry

I'd first try trouble shooting this by making sure the line is ok. from C500 connector to your dash. Then check to see if you have it routed properly on the motor. Electrical trouble shooting takes the longest on these swaps. I blew two altenators till I found the one wire causing the headaches. It was supposed to go to a hot in run wire, but wired it accidently to hot in start. It was the line that sensed how much voltage there was when the car is running, so it alwas read 0V and cranked the altenators output DOH!!

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My 3400 harness didn't have the tach output wire. I found a connector that was close enough and added it.

quote Originally posted by bandit307: Yes i am using the 7730 ECM. Does the wire for the Tach signal inside the cab not go to the C500 connector though? Im just going according to Ryan's diagrams. Also, what am i looking for in terms of a tach filter? Never worked with one so no idea what it looks like or which wire it should be on.

The tach feed to the inst. cluster indeed goes thru the C500 connector. If your 6-pin DIS electrical connector does not have a tach wire coming out of pin C, you will need to find one of these connectors off an older 3.1 or 2.8 that had DIS that does have this wire. Then you will need to hook this wire coming out of Pin C of the 6-way DIS connector to the white wire going to terminal C3 of the C500 connector (do NOT use the stock Fiero Tach filter).

As far as your low power issue is concerned, I recommend you go over your wiring again and recheck everything; also check to see if you have any trouble codes setting after you have run the engine. From what you describe it sounds like the engine is not getting the amount of timing advance it is supposed to.

-ryan

I have checked and checked the wiring to the DIS, when i disconect the bypass wire the timing dose change and it runs rougher. So does that mean everything is hooked up right? It just seems everything is hooked up right. I also thought it might be a fuel issue, But i am getting consistent 55 PSI pressure. Here is a short video of whats going on. You can here it bog when I open the throttle quick. But if I bring it up slowly it will rev up to a certain RPM that im not sure of cause there is no tach right now. But it eventually starts to loose power again. I will check my trouble codes tomorrow as well and see what it says.



EDIT: After looking at my video a few times. When i go to give it throttle and it bogs the fuel pressure goes up to 60PSI, could this be an injector issue?

[This message has been edited by bandit307 (edited 06-10-2008).]

I'm not familiar with the 3400 but got VERY familiar with the ignition system on my DOHC. If it's a DIS system you might want to check that the wires from the hall effect crank pickup sensor (in the block) to the ignition module are the correct way around. In fact it's a pretty easy task to swap them over (cut/solder/wrap) to test.
My DOHC had EXACTLY the the same symptoms (and sounded similar to yours before the fix), idled ok but no power/bogged. After replacing nearly everything I swapped those two wires over and it was fine! I had extended the wires on my car from the sensor to the module and even though I was convinced (and checked several times) that they were per the book they were still wrong. Someone else on here had the same issue with their DOHC and it fixed it.
I'm not sure why this issue occurs (at least on the DOHC) since I am convinced to this day I had those wires correctly wired. Maybe there's something else going on with the wiring that I did not understand that is causing the module to read the signal backwards or something, I don't really know. All I know is that it fixed it. At least it would eliminate it as a cause and it doesn't take much time to do.

And before anyone says it should not make a difference, it does. The signal from the sensor is a square(ish) wave and the ignition module triggers on the negative going edge (from my reading, took ages to find that tidbit and can't recall where it was now) so if the wires are the wrong way around the ignition module sees the down going edge at the wrong time relative to the crank position so the timing gets way off. Does not make much difference at low rpms as the ECM can compensate but as the RPMs increase the ecm has less and less time to 'adjust' the ignition timing. Eventually it gives up and resets everything and tries to start over (best I can figure anyway) with the resultant misfires, bogging etc.

Also I wouldn't be surprised to see you getting a code 42 (ignition coms problem), I had that all the time, it's just a symptom of the underlying timing problem but it can be misleading as I found out after trying 3 ECMs, 2 ignition modules and 2 sets of coils to no avail!

Re the fuel pressure issue, there's probably a vac line to the pressure regulator. When you open the throttle the vacuum in the system modulates the regulator and increases the pressure momentarily until the vacuum stabilizes. I suspect you are just seeing a side effect of that process caused by the bogging. I did the whole injector thing on mine, made no difference. I don't think you have an issue there.
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Dave

www.ltlfrari.com

[This message has been edited by ltlfrari (edited 06-10-2008).]

I have gotten a bit further. I had a faulty MAP sensor which i replaced and now and it runs alot better. If I open the throttle it will bog for a split second then rev right up. It still seems to struggle under load though. But after you rev off idle the engine is very responsive while its not under load. I am also now running 50psi at idle and up to 55psi during acceleration.

I do have another problem though, but im not to sure if it could be a factor of the struggle under load. I believe my TPS may not be good. I am getting good ground, steady 5V for reference but only .01V in all throttle position off the signal wire. So im under the assumption that the TPS is no longer working. This could be the issue for the slight blog from idle. But would it be the factor of the load issue?

Ok, so now everything seems to be getting proper voltage except my knock sensor which is recieving about 4.3V in the on position (supposed to be 2.5) and my O2 sensor which seems to recieve next to nothing for valtage. So i assume its a wiring issue on the O2 sensor since it is brand new.

I can take the car out and it will drive just still seems to be lacking in power, I have got it up to 4500rpm and seems to get there fine, just really slow. lol When i have it in the shop not under load it will still do a slight stumble from idle to WOT but will then rev right up no problem. Does seem to run a little rich right off idle aswell though as I get a nice little puff of black smoke. I hope its just O2 wiring I have left. It is the heated O2 sensor from the 3400.